Lithologic mapping of a forested montane terrain from Landsat 5 TM image |
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Authors: | Taufique H Mahmood Khaled Hasan Syed Humayun Akhter |
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Institution: | 1. Harold Hamm School of Geology and Geological Engineering, University of North Dakota, Grand Forks, ND, USA;2. Department of Geology, Austin Community College, Austin, TX, USA;3. Department of Geology, University of Dhaka, Dhaka, Bangladesh |
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Abstract: | Thick forest cover and poor infrastructures are the major hindrances for detailed lithologic mapping in an inaccessible montane landscape. To overcome these limitations, we utilize a Landsat 5 TM image to map lithology using vegetation and drainage pattern as an indicator of underlying rock types in a heavily forested region of the Chittagong Hill Tracts area located in southeastern Bangladesh. We use supervised and unsupervised classifiers for a vegetation-based approach while on-screen digitization is used for drainage patterns-based mapping. Field observations were used for mapping lithology and evaluating accuracy. Overall, our results agree well with the current geologic map and improve it by providing a more spatially detailed distribution of the sandstone and shale. The performances of all approaches are good at the inner and outer flanks of anticlines located in the study area while the drainage pattern mapping performs best at the mid-flank area. |
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Keywords: | Trellis dendritic sandstone shale supervised classification unsupervised classification |
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